Ibrexafungerp is efficacious in a neutropenic murine model of pulmonary mucormycosis as monotherapy and combined with liposomal amphotericin B

Ibrexafungerp (formerly SCY-078) is the first member of the triterpenoid class that prevents the synthesis of the fungal cell wall polymer β-(1,3)-D-glucan by inhibiting the enzyme glucan synthase. We evaluated the in vivo efficacy of ibrexafungerp against pulmonary mucormycosis using an established murine model. Neutropenic mice were intratracheally infected with either Rhizopus delemar or Mucor circinelloides. Treatment with placebo (diluent control), ibrexafungerp (30 mg/kg, PO BID), liposomal amphotericin B (LAMB 10 mg/kg IV QD), posaconazole (PSC 30 mg/kg PO QD), or a combination of ibrexafungerp plus LAMB or ibrexafungerp plus PSC began 16 h post-infection and continued for 7 days for ibrexafungerp or PSC and through day 4 for LAMB. Ibrexafungerp was as effective as LAMB or PSC in prolonging median survival (range: 15 days to >21 days) and enhancing overall survival (30%-65%) vs placebo (9 days and 0%; P < 0.001) in mice infected with R. delemar. Furthermore, median survival and overall percent survival resulting from the combination of ibrexafungerp plus LAMB were significantly greater compared to all monotherapies (P ≤ 0.03). Similar survival results were observed in mice infected with M. circinelloides. Monotherapies also reduce the lung and brain fungal burden by ~0.5-1.0log10 conidial equivalents (CE)/g of tissue vs placebo in mice infected with R. delemar (P < 0.05), while a combination of ibrexafungerp plus LAMB lowered the fungal burden by ~0.5-1.5log10 CE/g compared to placebo or any of the monotherapy groups (P < 0.03). These results are promising and warrant continued investigation of ibrexafungerp as a novel treatment option against mucormycosis.

Two New Triterpenes from Basidiomata of the Medicinal and Edible Mushroom, Laetiporus sulphureus

In the search for novel anti-infectives from natural sources, fungi, in particular basidiomycetes, have proven to still harbor so much potential in terms of secondary metabolites diversity. There have been numerous reports on isolating numerous secondary metabolites from genus Laetiporus. This study reports on two new triterpenoids, laetiporins C and D, and four known triterpenes from the fruiting body of L. sulphureus. The structures of the isolated compounds were elucidated based on their 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data in combination with high-resolution electrospray mass spectrometric (HR-ESIMS) data. Laetiporin C exhibited weak antifungal activity against Mucor hiemalis. Furthermore, the compounds showed weak antiproliferative activity against the mouse fibroblast L929 and human cancer cell lines, including KB-3-1, A431, MCF-7, PC-3 and A549.

A Case Series and Literature Review of Isavuconazole Use in Pediatric Patients with Hemato-oncologic Diseases and Hematopoietic Stem Cell Transplantation

We analyzed the use of isavuconazole (ISA) as treatment or prophylaxis for invasive fungal disease (IFD) in children with hemato-oncologic diseases. A multicentric retrospective analysis was performed among centers belonging to the Italian Association for Pediatric Hematology and Oncology (AIEOP). Pharmacokinetic (PK) monitoring was applied by a high-performance liquid chromatography-tandem mass spectrometry (HLPC-MS/MS) assay. Twenty-nine patients were studied: 10 during chemotherapy and 19 after allogeneic hematopoietic stem cell transplantation (HSCT). The patients consisted of 20 males and 9 females with a median age of 14.5 years (age range, 3 to 18 years) and a median body weight of 47 kg (body weight range, 15 to 80 kg). ISA was used as prophylaxis in 5 patients and as treatment in 24 cases (20 after therapeutic failure, 4 as first-line therapy). According to European Organization for Research and Treatment of Cancer (EORTC) criteria, we registered 5 patients with proven IFD, 9 patients with probable IFD, and 10 patients with possible IFD. Patients with a body weight of <30 kg received half the ISA dose; the others received ISA on the adult schedule (a 200-mg loading dose every 8 h on days 1 and 2 and a 200-mg/day maintenance dose); for all but 10 patients, the route of administration switched from the intravenous route to the oral route during treatment. ISA was administered for a median of 75.5 days (range, 6 to 523 days). The overall response rate was 70.8%; 12 patients with IFD achieved complete remission, 5 achieved partial remission, 5 achieved progression, and 3 achieved stable IFD. No breakthrough infections were registered. PK monitoring of 17 patients revealed a median ISA steady-state trough concentration of 4.91 mg/liter (range, 2.15 to 8.54 mg/liter) and a concentration/dose (in kilograms) ratio of 1.13 (range, 0.47 to 3.42). Determination of the 12-h PK profile was performed in 6 cases. The median area under the concentration-time curve from 0 to 12 h was 153.16 mg·h/liter (range, 86.31 to 169.45 mg·h/liter). Common Terminology Criteria for Adverse Events grade 1 to 3 toxicity (increased transaminase and/or creatinine levels) was observed in 6 patients, with no drug-drug interactions being seen in patients receiving immunosuppressants. Isavuconazole may be useful and safe in children with hemato-oncologic diseases, even in the HSCT setting. Prospective studies are warranted.

A Novel Resistance Pathway for Calcineurin Inhibitors in the Human-Pathogenic Mucorales Mucor circinelloides

Mucormycosis is an emerging lethal fungal infection in immunocompromised patients. Mucor circinelloides is a causal agent of mucormycosis and serves as a model system to understand genetics in Mucorales. Calcineurin is a conserved virulence factor in many pathogenic fungi, and calcineurin inhibition or deletion of the calcineurin regulatory subunit (CnbR) in Mucor results in a shift from hyphal to yeast growth. We analyzed 36 calcineurin inhibitor-resistant or bypass mutants that exhibited hyphal growth in the presence of calcineurin inhibitors or in the yeast-locked cnbRΔ mutant background without carrying any mutations in known calcineurin components. We found that a majority of the mutants had altered sequence in a gene, named here bycA (bypass of calcineurin). bycA encodes an amino acid permease. We verified that both the bycAΔ single mutant and the bycAΔ cnbRΔ double mutant are resistant to calcineurin inhibitor FK506, thereby demonstrating a novel mechanism of resistance against calcineurin inhibitors. We also found that the level of expression of bycA was significantly higher in the wild-type strain treated with FK506 and in the cnbRΔ mutants but was significantly lower in the wild-type strain without FK506 treatment. These findings suggest that bycA is a negative regulator of hyphal growth and/or a positive regulator of yeast growth in Mucor and that calcineurin suppresses expression of the bycA gene at the mRNA level to promote hyphal growth. BycA is involved in the Mucor hypha-yeast transition as our data demonstrate positive correlations among bycA expression, protein kinase A activity, and Mucor yeast growth. Also, calcineurin, independently of its role in morphogenesis, contributes to virulence traits, including phagosome maturation blockade, host cell damages, and proangiogenic growth factor induction during interactions with hosts.IMPORTANCEMucor is intrinsically resistant to most known antifungals, which makes mucormycosis treatment challenging. Calcineurin is a serine/threonine phosphatase that is widely conserved across eukaryotes. When calcineurin function is inhibited in Mucor, growth shifts to a less virulent yeast growth form, which makes calcineurin an attractive target for development of new antifungal drugs. Previously, we identified two distinct mechanisms through which Mucor can become resistant to calcineurin inhibitors involving Mendelian mutations in the gene for FKBP12, including mechanisms corresponding to calcineurin A or B subunits and epimutations silencing the FKBP12 gene. Here, we identified a third novel mechanism where loss-of-function mutations in the amino acid permease corresponding to the bycA gene contribute to resistance against calcineurin inhibitors. When calcineurin activity is absent, BycA can activate protein kinase A (PKA) to promote yeast growth via a cAMP-independent pathway. Our data also show that calcineurin activity contributes to host-pathogen interactions primarily in the pathogenesis of Mucor.

A Revised Species Concept for Opportunistic Mucor Species Reveals Species-Specific Antifungal Susceptibility Profiles

Recently, the species concept of opportunistic Mucor circinelloides and its relatives has been revised, resulting in the recognition of its classical formae as independent species and the description of new species. In this study, we used isolates of all clinically relevant Mucor species and performed susceptibility testing using the EUCAST reference method to identify potential species-specific susceptibility patterns. In vitro susceptibility profiles of 101 mucoralean strains belonging to the genus Mucor (72), the closely related species Cokeromyces recurvatus (3), Rhizopus (12), Lichtheimia (10), and Rhizomucor (4) to six antifungals (amphotericin B, natamycin, terbinafine, isavuconazole, itraconazole, and posaconazole) were determined. The most active drug for all Mucorales was amphotericin B. Antifungal susceptibility profiles of pathogenic Mucor species were specific for isavuconazole, itraconazole, and posaconazole. The species formerly united in M. circinelloides showed clear differences in their antifungal susceptibilities. Cokeromyces recurvatus, Mucor ardhlaengiktus, Mucor lusitanicus (M. circinelloides f. lusitanicus), and Mucor ramosissimus exhibited high MICs to all azoles tested. Mucor indicus presented high MICs for isavuconazole and posaconazole, and Mucor amphibiorum and Mucor irregularis showed high MICs for isavuconazole. MIC values of Mucor spp. for posaconazole, isavuconazole, and itraconazole were high compared to those for Rhizopus and the Lichtheimiaceae (Lichtheimia and Rhizomucor). Molecular identification combined with in vitro susceptibility testing is recommended for Mucor species, especially if azoles are applied in treatment.

Broad antifungal resistance mediated by RNAi-dependent epimutation in the basal human fungal pathogen Mucor circinelloides

Mucormycosis—an emergent, deadly fungal infection—is difficult to treat, in part because the causative species demonstrate broad clinical antifungal resistance. However, the mechanisms underlying drug resistance in these infections remain poorly understood. Our previous work demonstrated that one major agent of mucormycosis, Mucor circinelloides, can develop resistance to the antifungal agents FK506 and rapamycin through a novel, transient RNA interference-dependent mechanism known as epimutation. Epimutations silence the drug target gene and are selected by drug exposure; the target gene is re-expressed and sensitivity is restored following passage without drug. This silencing process involves generation of small RNA (sRNA) against the target gene via core RNAi pathway proteins. To further elucidate the role of epimutation in the broad antifungal resistance of Mucor, epimutants were isolated that confer resistance to another antifungal agent, 5-fluoroorotic acid (5-FOA). We identified epimutant strains that exhibit resistance to 5-FOA without mutations in PyrF or PyrG, enzymes which convert 5-FOA into the active toxic form. Using sRNA hybridization as well as sRNA library analysis, we demonstrate that these epimutants harbor sRNA against either pyrF or pyrG, and further show that this sRNA is lost after reversion to drug sensitivity. We conclude that epimutation is a mechanism capable of targeting multiple genes, enabling Mucor to develop resistance to a variety of antifungal agents. Elucidation of the role of RNAi in epimutation affords a fuller understanding of mucormycosis. Furthermore, it improves our understanding of fungal pathogenesis and adaptation to stresses, including the evolution of drug resistance.

The emerging infection mucormycosis causes high mortality in part because the major causative fungi, including Mucor circinelloides, are resistant to most clinically available antifungal drugs. We previously discovered an RNA interference-based resistance mechanism, epimutation, through which M. circinelloides develops transient resistance to the antifungal agent FK506 by altering endogenous RNA expression. We further characterize this novel mechanism by isolating epimutations in two genes that confer resistance to another antifungal agent, 5-fluoroorotic acid. Thus, we demonstrate epimutation can induce resistance to multiple antifungals by targeting a variety of genes. These results reveal epimutation plays a broad role enabling rapid and reversible fungal responses to environmental stresses, including drug exposure, and controlling antifungal drug resistance and RNA expression. As resistance to antifungals emerges, a deeper understanding of the causative mechanisms is crucial for improving treatment.

In vitro analysis of growth patterns of invasive fungal species on commonly used endonasal hemostatic agents

OBJECTIVE

Previous studies have not examined the potential role of endonasal hemostatic agents in facilitating growth of fungal species. We aim to determine the possibility of these to serve as a nutrient source for fungal growth.

METHODS

Cultures of Aspergillus, Fusarium, and Mucor were harvested and placed in solution in sterile saline at standardized high and low concentrations. Thrombin gelatin matrix, carboxyl methylcelluose, and potato starch derivative agents were prepared following manufacturer instructions and applied to two separate Petri dishes per agent. Each substrate was then inoculated with either high or low concentrations of fungal species. Negative and positive control plates with each organism were included. Dishes were sealed, incubated, and examined daily for fourteen days for microscopic and macroscopic growth.

RESULTS

Thrombin gelatin matrix was relatively resilient to growth, although Fusarium growth was noted on all packing material by day three. Carboxyl methylcellulose also supported growth of high-concentration Mucor appreciated on day five. The potato starch derivative supported fulminant growth of all fungal species.

CONCLUSIONS

Endonasal hemostatic agents may be nutrient sources that facilitate growth of fungal species. This may be a consideration in a surgeon's decision to use a hemostatic agent. Prompt initial post-operative debridement may be warranted in select patients. Our findings serve as a model for further testing of fungal growth on other hemostatic materials. Future studies are needed to confirm the clinical significance of these findings in vivo.

Pestynol, an Antifungal Compound Discovered Using a Saccharomyces cerevisiae 12geneΔ0HSR-iERG6-Based Assay

The multidrug-sensitive budding yeast, Saccharomyces cerevisiae 12geneΔ0HSR-iERG6, is very useful in antifungal screens. A novel compound, named pestynol (1), was discovered from a culture of the fungus Pestalotiopsis humus FKI-7473 using the multidrug-sensitive yeast. The structure of 1 was elucidated by NMR studies and modified Mosher's method as (1 R,2 R,3 R,4 R)-( E)-5-(7,11-dimethyl-3-methylenedodeca-6,10-dien-1-yn-1-yl)cyclohex-5-ene-1,2,3,4-tetraol. Compound 1 showed antimicrobial activity against the Gram-positive bacteria, Klebsiella pneumoniae, and S. cerevisiae 12geneΔ0HSR-iERG6 and Mucor racemosus, but displayed only weak cytotoxicity against various human cancer cell lines. Compound 1 displayed antifungal activities against S. cerevisiae 12geneΔ0HSR-iERG6 and Mucor racemosus at 10 μg/disc.

Activity of selected essential oils on spoiling fungi cultured from Marzolino cheese

Microscopic fungi can be present on a variety of foodstuff, including cheese. They can be responsible for fungal spoilage, causing sensory changes making food unacceptable for human consumption, and posing severe health concerns. Furthermore, some of these organisms are able to resist antimicrobial preservatives provided for by law. Antifungal activity of 15 chemically defined EOs, alone and in mixture, were checked by a microdilution test against isolates of Penicillium funiculosum and Mucor racemosus cultured from rinds of Marzolino, a typical Italian fresh pecorino cheese. Origanum vulgare yielded the lowest MIC values, followed by Salvia sclarea, Ocimum basilicum and Cymbopogon citratus, while Citrus paradisi and Citrus limon were not active. All mixtures showed antifungal activity at lower concentration with respect to MIC values of each EO component, when not in combination. This study is the first to describe the setting up of EOs mixtures to limit spoiling moulds.

Morphological evolution of various fungal species in the presence and absence of aluminum oxide microparticles: Comparative and quantitative insights into microparticle-enhanced cultivation (MPEC)

The application of microparticle‐enhanced cultivation (MPEC) is an attractive method to control mycelial morphology, and thus enhance the production of metabolites and enzymes in the submerged cultivations of filamentous fungi. Unfortunately, most literature data deals with the spore‐agglomerating species like aspergilli. Therefore, the detailed quantitative study of the morphological evolution of four different fungal species (Aspergillus terreus, Penicillium rubens, Chaetomium globosum, and Mucor racemosus) based on the digital analysis of microscopic images was presented in this paper. In accordance with the current knowledge, these species exhibit different mechanisms of agglomerates formation. The standard submerged shake flask cultivations (as a reference) and MPEC involving 10 μm aluminum oxide microparticles (6 g·L⁻¹) were performed. The morphological parameters, including mean projected area, elongation, roughness, and morphology number were determined for the mycelial objects within the first 24 hr of growth. It occurred that heretofore observed and widely discussed effect of microparticles on fungi, namely the decrease in pellet size, was not observed for the species whose pellet formation mechanism is different from spore agglomeration. In the MPEC, C. globosum developed core‐shell pellets, and M. racemosus, a nonagglomerative species, formed the relatively larger, compared to standard cultures, pellets with distinct cores.

Activity of Salvia dolomitica and Salvia somalensis Essential Oils against Bacteria, Molds and Yeasts

Essential oils (EOs) from Salvia dolomitica and Salvia somalensis, widely employed in the cosmetic and perfume industry, were analyzed for composition and tested against bacterial and fungal pathogens isolated from clinical and environmental specimens. The analyses were carried out against Staphylococcus aureus, Staphylococcus pseudointermedius, Pseudomonas aeruginosa, Escherichia coli, Streptococcus canis, Streptococcus pyogenes, Klebsiella pneumoniae, Proteus mirabilis, Microsporum canis, Microsporum gypseum, Trichophyton mentagrophytes, Aspergillus niger, Aspergillus flavus, Candida albicans, Candida krusei, Mucor sp. and Trichothecium roseum. Both EOs showed similar percentages of total monoterpenes and sesquiterpene hydrocarbons. The main constituents were 1,8-cineole and β-caryophyllene in S. dolomitica and bornyl acetate and camphor in S. somalensis. The selected EOs have no relevant antifungal or antibacterial activities if compared to conventional drugs.

A protein complex bearing an oxidase with napthalene dihydrodiol dehydrogenase activity is induced in Mucor circinelloides strain YR-1 during growth on polycyclic aromatic compounds

Fungi are organisms capable of growing in a myriad of conditions and respond to counteract environmental cues. Several locations in the world are polluted with oil and its derivatives, and some microorganisms tolerant to these compounds have been isolated. Some fungi can grow in the presence of molecules such as polycyclic aromatic hydrocarbons as sole carbon sources. In this report, we further characterized the induced enzymes with phenanthrene from Mucor circinelloides YR-1 strain, isolated from a polluted field near a petrochemical facility in México. We identified a putative oxidase that is induced when growth with phenanthrene as sole carbon source at a pH of 8.5 and is NADP⁺ dependent. We show that this enzyme bears naphthalene dihydrodiol dehydrogenase activity with substrate preference for the cis-naphthalene over the trans-naphthalene, with an optimal pH in the range of 8-10. Mass spectrometry analysis revealed that the induced enzyme belongs to the NADP⁺ oxidase family enzymes with the typical Rossmann-fold for NADP⁺ binding. This enzyme seems to form a high molecular weight structure (~ 541 kDa) and with a monomer of 57 kDa, suggesting that the multimer is constituted of 10 subunits. Our findings contribute to understanding of the roles that dihydrodiol dehydrogenases have in organisms exposed to toxic compounds in the environment and can regulate their expression.

Longterm storage of post-packaged bread by controlling spoilage pathogens using Lactobacillus fermentum C14 isolated from homemade curd

One potent lactic acid bacterial strain C14 with strong antifungal activity was isolated from homemade curd. Based on morphological as well as biochemical characters and 16S rDNA sequence homology the strain was identified as Lactobacillus fermentum. It displayed a wide antimicrobial spectrum against both Gram-positive and Gram-negative pathogenic bacteria, and also against number of food spoilage, plant and human pathogenic fungi. The cell free supernatant (CFS) of the strain C14 was also effective against the fungi tested. Inhibition of radial growth of Penicillium digitatum, Trichophyton rubrum and Mucor sp. was noticed in the presence of CFS of C14 even at low concentration (1%). More than 94.3 ± 1.6% and 91.5 ± 2.2% inhibition of conidial germination of P. digitatum and Mucor sp. were noticed in the presence of 10-fold-concentrated CFS of C14. Massive deformation of the fungal mycelia was observed by SEM studies, and losses of cellular proteins and DNA are also evident upon its treatment with C14. HPLC analysis revealed the presence of phenyl lactic acid, lactic acid along with some unidentified compounds in the antifungal extract. Challenge experiment showed immense potential of the strain C14 in preventing the spoilage of bread samples caused by Mucor sp. and Bacillus subtilis. The bread samples remained fresh upto 25 days even after inoculation with Mucor sp. (3.7 × 104 spores /ml) and B. subtilis (4.6 × 104 CFU /ml). Along with the antifungal properties, the isolated lactic acid bacterial strain also showed very good antioxidant activities. Unchanged level of liver enzymes serum glutamic pyruvic transaminase and serum glutamic oxaloacetic transaminase in albino mice upon feeding with C14 also suggested non-toxic nature of the bacterial isolate.

Alleviation of heavy metal toxicity and phytostimulation of Brassica campestris L. by endophytic Mucor sp. MHR-7

Heavy metal (HM) pollution is of great concern in countries like Pakistan where a huge proportion of human population is exposed to it. These toxic metals are making their way from water bodies to soil where it not only interferes with plant growth and development but also initiates serious health issues in human consuming the produce of such soils. Bioremediation is one of the most viable and efficient solution for the problem. Purpose of the current study was to isolate endophytic fungi from plants grown on HM contaminated soil and screen them for their ability to tolerate multiple HM including chromium (Cr⁶⁺), manganese (Mn²⁺), cobalt (Co²⁺), copper (Cu²⁺) and zinc (Zn²⁺). Out of 27 isolated endophytes, only one strain (MHR-7) was selected for multiple heavy metals tolerance. The strain was identified as Mucor sp. by 18S and 28S ribosomal RNA internal transcribed spacer (ITS) 1 and 4 sequence homology. The strain effectively tolerated up to 900µgmL^-1 of these heavy metals showing no remarkable effect on its growth. The adverse effect of the heavy metals, measured as reduction of the fungal growth increased with increasing concentration of the metals. The strain was able to remove 60-87% of heavy metals from broth culture when supplied with 300µgmL^-1 of these metals. A trend of decline in bioremediation potential of the strain was observed with increasing amount of metals. The strain removed metals by biotransformation and/or accumulation of heavy metal in its hyphae. Application of Mucor sp. MHR-7 locked down HM in tis mycelium thereby making them less available to plant root reducing HM uptake and toxicity in mustard. Besides its bioremediation potential, the strain was also able to produce IAA, ACC deaminase and solubilize phosphate making it excellent phytostimulant fungus. It is concluded that MHR-7 is an excellent candidate for use as biofertilizer in fields affected with heavy metals.

[Synthesis and antifungal activities of N-1,3,4-thiadiazol-2-yl-4-oxo-thiochroman-2-yl-formamide derivatives]

Thiochromanones and 1,3,4-thiadiazoles as heterocyclic compounds have broad biological activities. In order to find novel compounds with antifungal bioactivity, substituted thiophenol and maleic anhydride were used to synthesize the intermediate 4-oxothiochromane-2-carboxylic acid. It was reacted with 2-amino-1,3,4-thiadiazole to get fourteen target compounds containing 1,3,4-thiadiazole moiety. The structures of the obtained compounds were confirmed by 1H NMR, 13C NMR and HR-MS. All compounds were investigated for antifungal activity via microdilution broth method. The results showed that the target compounds 3a and 3c to Epidermophyton floccosum and Mucor racemosus exhibited better antifungal activity than the positive control fluconazole, in which the minimum inhibition concentration can reach 8 μg·mL−1 and 16 μg·mL−1. Compound 3e showed significant inhibitory activity to Helminthosporium maydis, Sclerotinia sclerotiorum and Botrytis cinerea compared with that of the positive control carbendazim. Compound 3b exhibited inhibitory activity to Helminthosporium maydis better than the positive control carbendazim.

Antifungal activity of 1'-homo-N-1,2,3-triazol-bicyclic carbonucleosides: A novel type of compound afforded by azide-enolate (3+2) cycloaddition

The first report of 1'-homo-N-1,2,3-triazol-bicyclic carbonucleosides (7a and 7b) is described herein. Azide-enolate (3+2) cycloaddition afforded the synthesis of this novel type of compound. Antifungal activity was evaluated in vitro against four filamentous fungi (Aspergillus fumigatus, Trichosporon cutaneum, Rhizopus oryzae and Mucor hiemalis) as well as nine species of Candida spp. as yeast specimens. These pre-clinical studies suggest that compounds 7a and 7b are promising candidates for complementary biological studies due to their good activity against Candida spp.

Fungus-associated bacteriome in charge of their host behavior

Bacterial-fungal interactions are widespread in nature and there is a growing number of studies reporting distinct fungus-associated bacteria. However, little is known so far about how shifts in the fungus-associated bacteriome will affect the fungal host's lifestyle. In the present study, we describe for the first time the bacterial community associated with the saprotrophic fungus Mucor hiemalis, commonly found in soil and rhizosphere. Two broad-spectrum antibiotics that strongly altered the bacterial community associated with the fungus were applied. Our results revealed that the antibiotic treatment did not significantly reduce the amount of bacteria associated to the fungus but rather changed the community composition by shifting from initially dominating Alpha-Proteobacteria to dominance of Gamma-Proteobacteria. A novel approach was applied for the isolation of fungal-associated bacteria which also revealed differences between bacterial isolates obtained from the original and the antibiotic-treated M. hiemalis. The shift in the composition of the fungal-associated bacterial community led to significantly reduced fungal growth, changes in fungal morphology, behavior and secondary-metabolites production. Furthermore, our results showed that the antibiotic-treated isolate was more attractive and susceptible to mycophagous bacteria as compared to the original isolate. Overall, our study highlights the importance of the fungus-associated bacteriome for the host's lifestyle and interactions and indicate that isolation with antibacterials is not sufficient to eradicate the associated bacteria.

Sorazolons, Carbazole Alkaloids from Sorangium cellulosum Strain Soce375

Sorazolons A (1) to E2 (9) were isolated from Sorangium cellulosum strain Soce375. Their molecular structures were elucidated using extensive HRESIMS and NMR analysis. The absolute configuration of sorazolon A (1) was determined by comparison of the experimental CD spectrum with quantum chemical calculated spectra for both enantiomers. Sorazolons D2 (7), E (8), and E2 (9) exhibit a moderate cytotoxic activity against mouse fibroblast cell line L929 with IC50 values between 5.0 μM and 0.09 mM.

Effects of Plant Growth Hormones on Mucor indicus Growth and Chitosan and Ethanol Production

The objective of this study was to investigate the effects of indole-3-acetic acid (IAA) and kinetin (KIN) on Mucor indicus growth, cell wall composition, and ethanol production. A semi-synthetic medium, supplemented with 0–5 mg/L hormones, was used for the cultivations (at 32 °C for 48 h). By addition of 1 mg/L of each hormone, the biomass and ethanol yields were increased and decreased, respectively. At higher levels, however, an inverse trend was observed. The glucosamine fraction of the cell wall, as a representative for chitosan, followed similar but sharper changes, compared to the biomass. The highest level was 221% higher than that obtained without hormones. The sum of glucosamine and N-acetyl glucosamine (chitin and chitosan) was noticeably enhanced in the presence of the hormones. Increase of chitosan was accompanied by a decrease in the phosphate content, with the lowest phosphate (0.01 g/g cell wall) being obtained when the chitosan was at the maximum (0.45 g/g cell wall). In conclusion, IAA and KIN significantly enhanced the M. indicus growth and chitosan production, while at the same time decreasing the ethanol yield to some extent. This study shows that plant growth hormones have a high potential for the improvement of fungal chitosan production by M. indicus.

Antimicrobial, antitumor and brine shrimp lethality assay of Ranunculus arvensis L. extracts

To investigate the antitumor activity, brine shrimp lethality assay, antibacterial and antifungal activity of Methanol Extract (ME), Water Extract (WE), Acetone Extract (AE), Chloroform Extract (CE), Methanol-Water Extract (MWE), Methanol-Acetone Extract (MAE), Methanol-Chloroform Extract (MCE) of Ranunculus arvensis (L.). Antitumor activity was evaluated with Agrobacterium tumefaciens (At10) induced potato disc assay. Cytotoxicity was evaluated with brine shrimp lethality assay. Antibacterial activity was evaluated with six bacterial strains including Escherichia coli, Enterobacter aerogenes, Bordetella bronchiseptica, Klebsiella pneumoniae, Micrococcus luteus and Streptococcus anginosus and antifungal screening was done against five fungal strains including Aspergillus niger, A. flavus, A. fumigates, Fusarium solani and Mucor species by using disc diffusion method. Best antitumor activity was obtained with ME and WE, having highest IC50 values 20.27 ± 1.62 and 93.01 ± 1.33μg/disc. Brine shrimp lethality assay showed LC50 values of AE, MAE and ME were obtained as 384.66 ± 9.42μg/ml, 724.11 ± 8.01μg/ml and 978.7 ±8.01 μg/ml respectively. WE of R. arvensis revealed weak antimicrobial result against the tested microorganisms. On the other hand, the antifungal activity of the plant extracts was found to be insignificant. These findings demonstrate that extracts of R. arvensis possesses significant antitumor activity. Further extensive study is necessary to assess the therapeutic potential of the plant.

Biosynthesis, characterization and enzymatic transesterification of single cell oil of Mucor circinelloides--a sustainable pathway for biofuel production

The filamentous fungus Mucor circinelloides URM 4182 was tested to determine its ability to produce single-cell oil suitable for obtaining biodiesel. Cell growth and lipid accumulation were investigated in a medium containing glucose as the main carbon source. A microwave-assisted ethanol extraction technique (microwave power ⩽200 W, 50-60 °C) was established and applied to lipid extraction from the fungal hyphae to obtain high lipid concentration (44%wt) of the dry biomass, which was considerably higher than the quantity obtained by classical solvent methods. The lipid profile showed a considerable amount of oleic acid (39.3%wt), palmitic acid (22.2%wt) and γ-linoleic acid (10.8%wt). Biodiesel was produced by transesterification of the single-cell oil with ethanol using a immobilized lipase from Candida antarctica (Novozym® 435) as the catalyst. (1)H NMR and HPLC analyses confirmed conversion of 93% of the single-cell oil from M. circinelloides into ethyl esters (FAEE).

Balticidins A-D, antifungal hassallidin-like lipopeptides from the Baltic Sea cyanobacterium Anabaena cylindrica Bio33

Balticidins A-D (1-4), four new antifungal lipopeptides, were isolated from the laboratory-cultivated cyanobacterium Anabaena cylindrica strain Bio33 isolated from a water sample collected from the Baltic Sea, Rügen Island, Germany. Fractionation of the 50% aqueous MeOH extract was performed by bioassay-guided silica gel column chromatography followed by SPE and repeated reversed-phase HPLC. The main fraction containing the compounds exhibited a strong and specific antifungal activity with inhibition zones in an agar-diffusion assay from 21 to 32 mm against Candida albicans, Candida krusei, Candida maltosa, Aspergillus fumigatus, Microsporum gypseum, Mucor sp., and Microsporum canis. The structures were elucidated by multidimensional (1)H and (13)C NMR spectroscopy, HRESIMS, amino acid analysis, and sugar analysis. Spectroscopic data analysis afforded an unambiguous sequence of R.CHO(S1).CHOH.CONH-Thr(1)-Thr(2)-Thr(3)-HOTyr(4)-Dhb(5)-D-Gln(6)-Gly(7)-NMeThr(8)(S2)-L-Gln COOH(9), in which Dhb is dehydroaminobutyric acid, S1 is d(-)-arabinose-(3-1)-D-(+)-galacturonic acid, S2 is D-(+)-mannose, and R is the aliphatic residue -C13H26Cl or -C13H27. Besides NMeThr, D-allo-Thr, D-Thr, and L-Thr were identified, but the position of the enantiomers in the sequence is not clear. The four balticidins differ in their cyclic (2, 4)/linear (1, 3) core and the presence (1, 2)/absence (3, 4) of chlorine in the aliphatic unit.

Pyrronazols, metabolites from the myxobacteria Nannocystis pusilla and N. exedens, are unusual chlorinated pyrone-oxazole-pyrroles

The chlorinated pyrrole-oxazole-pyrones pyrronazol A (1), pyrronazol A2 (2), and pyrronazol B (3) were isolated from Nannocystis pusilla strain Ari7, and two chlorinated pyrrole-oxazole isomers, pyrronazols C1 (4) and C2 (5), were isolated from N. pusilla strain Na a174. HRESIMS, NMR, and X-ray crystallographic analysis was used in the structure elucidation including the absolute configuration of pyrronazol A (1). In addition to pyrronazols, 1,6-phenazine-diol (6) and its glycosyl derivative, 1-hydroxyphenazin-6-yl-α-d-arabinofuranoside (7), were isolated and identified from the culture broth of N. pusilla strain Ari7. When tested for biological activity against bacteria, fungi, and yeasts, 1 showed weak antifungal activity against Mucor hiemalis (MIC 33.3 μg/mL) but no antibacterial activity, while 6 showed weak antibacterial and antifungal activity (MIC 33.3 μg/mL) against some of the strains tested. In cell culture experiments 1 showed no significant cytotoxicity, while 6 was active against several cell lines, especially the human ovarian carcinoma cells SK-OV-3 (LD50 2.59 μM).

Successful treatment of a necrotizing fasciitis patient caused by Mucor indicus with amphotericin B and skin grafting

Cutaneous mucormycosis, an uncommon disease caused by Mucorales, predominantly occurs in immunocompromised host. The present case is a primary cutaneous mucormycosis due to Mucor indicus in an immunocompetent individual. It is with the features of necrotizing fasciitis over the right pretibial area. We are presenting this case owing to its rarity and the successful treatment with amphotericin B and skin grafting.

Hurgadacin: a new steroid from Sinularia polydactyla

Hurgadacin (1), a 24,25-bishomo-26-methylenecholesterol was isolated from the soft coral Sinularia polydactyla, collected from the Red Sea, near Hurghada at the Egyptian coast. The new steroid 1 was isolated together with the closely related polyhydroxy steroids 24-methylenecholestane-3β,5α,6β-triol (2) and 24-methylenecholestane-1α,3β,5α,6β,11α-pentol (3), in addition to the sesquiterpene lactiflorenol (4) and the trinorcarotenolide acetate peridinin (5), The structures of the isolated compounds were confirmed by intensive studies of their 1D and 2D NMR spectra and mass data. The antimicrobial and cytotoxic activities of the soft coral extract and the corresponding constituents were evaluated against diverse pathogenic microorganisms and brine shrimps, respectively.

Indiacens A and B: prenyl indoles from the myxobacterium Sandaracinus amylolyticus

The gliding bacterium Sandaracinus amylolyticus, strain NOSO-4T, was recently characterized as the first representative of a new myxobacterial genus. A screening of the culture broth for antibiotically active metabolites followed by isolation and characterization revealed two unique 3-formylindol derivatives, indiacen A (1) and its chloro derivative indiacen B (2). Both are active against Gram-positive and Gram-negative bacteria as well as the fungus Mucor hiemalis. The biosynthetic origin of the isoprene-like side chain in 1 and 2 was studied by in vivo feeding experiments with ¹³C-labeled precursors.

Controlling wildlife fungal disease spread: in vitro efficacy of disinfectants against Batrachochytrium dendrobatidis and Mucor amphibiorum

Chytridiomycosis in amphibians, and mucormycosis in the platypus Ornithorhynchus anatinus and amphibians, are serious fungal diseases affecting these aquatic taxa. In Tasmania, Australia, the fungi that cause these diseases overlap in range along with Phytophthora cinnamomi (Pc), an invasive fungal plant pathogen. To identify disinfectants that may be useful to reduce anthropogenic spread of these fungi to uninfected wilderness areas, for example by bush walkers and forestry or fire-fighting operations, we tested 3 disinfectants and a fire-fighting foam against Mucor amphibiorum (Ma) and tested 1 disinfectant and the foam against Batrachochytrium dendrobatidis (Bd). Combining the present study with previous work we found Bd was more susceptible to all 4 chemicals than Ma. Phytoclean, a disinfectant used at 2 to 10% for 30 s to control Pc, killed cultures of Bd at 0.075% and Ma at 5%, when also applied for 30 s. The disinfectant F10sc was not effective against Ma at standard exposures, but previous work shows Bd is killed at 0.03% with a 1 min exposure. Path-X is effective against Bd at 0.001% with a 30 s exposure and killed Ma at 1% with a 5 min exposure. Forexpan S, a foam added to water at 0.1 to 1% to control forest fires, killed Bd but not Ma when used at 1% for 2 min. Therefore, Phytoclean and Path-X have broader efficacy, although Path-X has not been trialled against Pc. Interestingly a positive mating strain of Ma (from a platypus) was more resistant to disinfectants than a negative strain (from a frog). Current protocols against Pc that involve high concentrations (10%) of Phytoclean are likely to reduce spread of pathogenic wildlife fungi, which is important for protecting biodiversity.

Paeciloside A, a new antimicrobial and cytotoxic polyketide from Paecilomyces sp. strain CAFT156

Paeciloside A (1) and eight known compounds, acremoauxin A (2), farinosones A (3) and B (4), 1,5-dideoxy-3-C-methyl-arabitol (5), ergosterol, ergosterol peroxide, cerebroside C, and adenosine, were isolated from cultures of Paecilomyces sp. CAFT156, an endophytic fungus occurring in Enantia chlorantha Oliv (Annonaceae) leaves. The structure of the new compound 1 was elucidated using MS, UV, 1D and 2D NMR experiments, while its absolute configuration was established by subsequent single-crystal X-ray diffraction analysis using copper Kα radiation and invariom nonspherical scattering factors. Paeciloside A (1) and compounds 2, 4, and 5 displayed inhibitory effects on two gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus at a concentration of 40 µg per paper disk and moderate cytotoxicity towards brine shrimp larvae (Artemia salina). This study presents the first report on an endophytic fungus isolated from E. chlorantha Oliv and its natural products.

Rapamycin exerts antifungal activity in vitro and in vivo against Mucor circinelloides via FKBP12-dependent inhibition of Tor

The zygomycete Mucor circinelloides is an opportunistic fungal pathogen that commonly infects patients with malignancies, diabetes mellitus, and solid organ transplants. Despite the widespread use of antifungal therapy in the management of zygomycosis, the incidence of infections continues to rise among immunocompromised individuals. In this study, we established that the target and mechanism of antifungal action of the immunosuppressant rapamycin in M. circinelloides are mediated via conserved complexes with FKBP12 and a Tor homolog. We found that spontaneous mutations that disrupted conserved residues in FKBP12 conferred rapamycin and FK506 resistance. Disruption of the FKBP12-encoding gene, fkbA, also conferred rapamycin and FK506 resistance. Expression of M. circinelloides FKBP12 (McFKBP12) complemented a Saccharomyces cerevisiae mutant strain lacking FKBP12 to restore rapamycin sensitivity. Expression of the McTor FKBP12-rapamycin binding (FRB) domain conferred rapamycin resistance in S. cerevisiae, and McFKBP12 interacted in a rapamycin-dependent fashion with the McTor FRB domain in a yeast two-hybrid assay, validating McFKBP12 and McTor as conserved targets of rapamycin. We showed that in vitro, rapamycin exhibited potent growth inhibitory activity against M. circinelloides. In a Galleria mellonella model of systemic mucormycosis, rapamycin improved survival by 50%, suggesting that rapamycin and nonimmunosuppressive analogs have the potential to be developed as novel antifungal therapies for treatment of patients with mucormycosis.

Chromophenazines from the terrestrial Streptomyces sp. Ank 315

The new chromophenazines A-F [9-methyl-5-(3'-methylbut-2'-enyl)-5H-benzo[a]phenazin-7-one (1a), 9-methyl-5-(3'-methylbut-2'-enyl)-7-oxo-5,7-dihydrobenzo[a]phenazine-1-carboxylic acid (1b), 5-(3'-methylbut-2'-enyl)-7-oxo-5,7-dihydrophenazine-1-carboxamide (2), 3-benzoyl-5-(3'-methylbut-2'-enyl)-5,10-dihydrophenazine-1-carboxylic acid (5a), 3,7-dibenzoyl-5-(3'-methylbut-2'-enyl)-5,10-dihydrophenazine-1-carboxylic acid (5b), and 3,7-dibenzoyl-5-(3'-methylbut-2'-enyl)-5,10-dihydrophenazine-1-carboxamide (5c)], together with phenazine-1-carboxylic acid, 1-phenazinecarboxamide, 1-phenazinol, tryptophol, and anthranilic acid, were isolated from Streptomyces sp. Ank 315. The structures of the new compounds were established on the basis of spectroscopic data, 1D NOE, 2D NMR, and ESIMS measurements and comparison with literature values.

Biosynthesis, extraction, purification, and analysis of trisporoid sexual communication compounds from mated cultures of Blakeslea trispora

The zygomycete Blakeslea trispora produces high amounts of the general zygomycete β-carotene-derived sexual signal compounds, the trisporoids. These can be isolated from the culture medium and purified by extraction with organic solvents followed by thin layer chromatography. Concentration is determined spectrophotometrically using specific extinction coefficients established for some members of this compound family. The effect of the extraction and activity of the isolated compounds is best tested physiologically, exploiting the ability of trisporoids to induce the formation of sexually committed hyphae, the zygophores, in other zygomycete species. Methods for B. trispora culture, trisporoid extraction, and further analyses of trisporoids are described in this chapter.

A pilot study on lignocelluloses to ethanol and fish feed using NMMO pretreatment and cultivation with zygomycetes in an air-lift reactor

A complete process for the production of bioethanol and fungal biomass from spruce and birch was investigated. The process included milling, pretreatment with N-methylmorpholine-N-oxide (NMMO), washing of the pretreated wood, enzymatic hydrolysis, and cultivation of the zygomycetes fungi Mucor indicus. Investigated factors included wood chip size (0.5-16 mm), pretreatment time (1-5h), and scale of the process from bench-scale to 2m high air-lift reactor. Best hydrolysis yields were achieved from wood chips below 2mm after 5h of pretreatment. Ethanol yields (mg/g wood) of 195 and 128 for spruce, and 175 and 136 for birch were achieved from bench-scale and airlift, respectively. Fungal biomass yields (mg/g wood) of 103 and 70 for spruce, and 86 and 66 for birch from bench scale and airlift respectively were simultaneously achieved. NMMO pretreatment and cultivation with M. indicus appear to be a good alternative for ethanol production from birch and spruce.

Characterization of Cd- and Pb-resistant fungal endophyte Mucor sp. CBRF59 isolated from rapes (Brassica chinensis) in a metal-contaminated soil

To better understand the characteristics of fungal endophytes in the development of effective phytoremediation of heavy metals, the objectives of this study were to isolate a fungal endophyte tolerant Cd and Pb from rape roots grown in a heavy metal-contaminated soil, to characterize the metal-resistant fungal endophyte, and to assess its potential applications in removal of Cd and Pb from contaminated solutions and experimental soil. The isolate CBRF59 was identified as Mucor sp. based on morphological characteristics and phylogenetic analysis. From a Cd solution of 2.0mM, the maximum biosorption capacity of Cd by dead biomass of Mucor sp. CBRF59 was 108 mg g(-1). Under the same conditions, the bioaccumulation capacity of Cd by active biomass of the strain was 173 mg g(-1). The bioaccumulation capacity of Pb by active biomass of the strain was significantly lower than that by dead biomass in the initial Pb concentrations from 1.0 to 2.0mM. The ratio of Pb to Cd and initial pH values in the mixed Cd+Pb solutions affected the bioaccumulation and biosorption capacities of the metals by CBRF59. The addition of the active mycelia of CBRF59 significantly increased the availability of soil Pb and Cd by 77% and 11.5-fold, respectively. The results showed that the endophytic fungus was potentially applicable for the decontamination of metal-polluted media.

Design of novel 4-hydroxy-chromene-2-one derivatives as antimicrobial agents

This paper presents the design of novel 4-hydroxy-chromene-2 one derivatives, based on previously obtained minimal inhibitory concentration values (MICs), against twenty four microorganism cultures, gram positive and negative bacteria and fungi. Two of our compounds, 3b (MIC range 130-500 microg/mL) and 9c (31.25-62.5 microg/mL), presented high potential antimicrobial activity. The compound 9c had equal activity to the standard ketoconazole (31.25 microg/mL) against M. mucedo. Enlarged resistance of S. aureus, E. coli and C. albicans on the effect of potential drugs and known toxicity of coumarin antibiotics, motivated us to establish SAR and QSAR models of activity against these cultures and correlate biological activity, molecular descriptors and partial charges of functional groups to explain activity and use for the design of new compounds. The QSAR study presents essential relation of antimicrobial activity and dominant substituents, 4-hydroxy, 3-acetyl and thiazole functional groups, also confirmed through molecular docking. The result was ten new designed compounds with much improved predicted inhibition constants and average biological activity.

Modified phenazines from an Indonesian Streptomyces sp

Fractionation of the extract from the Indonesian Streptomyces sp. ICBB8198 as directed by the antibacterial activity delivered the known phenazine antibiotics griseoluteic acid (1a) and griseolutein A (1b), as well as two new phenazine derivatives (2 and 3). In addition, the known compounds spirodionic acid, dihydrosarkomycins, and 6-ethyl-4-hydroxy-3,5-dimethyl-2H-pyran-2-one (4a), along with the new pyrone 3,6-diethyl-4-hydroxy-5-methyl-2H-pyran-2-one (4b), were isolated. We report here the isolation, structure elucidation, and antibiotic activity of the new metabolites as well as a hypothetical pathway for the formation of the new phenazine derivatives.

The influence of organ, season and drying method on chemical composition and antioxidant and antimicrobial activities of Juniperus phoenicea L. essential oils

BACKGROUND

Juniperus phoenicea is an important medicinal plant. In the present study, essential oils (18 samples) from leaves and berries of Juniperus phoenicea L. (Cupressaceae), obtained by various drying methods and in different collection months, were analysed by gas chromatography-mass spectrometry and also evaluated for in vitro antimicrobial and antioxidant activities. Correlations were studied between antimicrobial activity and the chemical composition of essential oils.

RESULTS

Sixty-seven compounds were identified in essential oils, representing 97.7-100%. Essential oils were dominated by monoterpenes and sesquiterpenes, which presented 35.0-93.3% and 6.7-62.0%, respectively, depending of organ, season and drying method. Antimicrobial tests showed that essential oils strongly inhibited the growth of Gram-positive microorganisms and Mucor ramamnianus, but was inactive against Gram-negative strains. Antioxidant activity was tested using the ABTS radical-scavenging assay. Most samples showed good activity (the best IC(50) = 41.7 + or - 1.5 mg L(-1)).

CONCLUSIONS

It could be concluded that drying of leaves of J. phoenicea in the sun and berries in oven-drying was more suitable and was recommended for obtaining higher essential oil yield, but for a higher percentage of some special components such as alpha-pinene and delta-3-carene shade-drying was more suitable.

Ruthenium(II) chalconate complexes: Synthesis, characterization, catalytic, and biological studies

A series of new hexa-coordinated ruthenium(II) carbonyl complexes of the type [RuCl(CO)(EPh(3))(B)(L)] (E = P or As; B = PPh(3), AsPh(3) or Py; L = 2'-hydroxychalcones) have been prepared by reacting [RuHCl(CO)(EPh(3))(2)(B)] (E = P or As; B = PPh(3), AsPh(3) or Py) with 2'-hydroxychalcones in benzene under reflux. The new complexes have been characterized by analytical and spectral (IR, electronic, (1)H, (31)P and (13)C NMR) data. Based on the above data, an octahedral structure has been assigned for all the complexes. The new complexes exhibit catalytic activity for the oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N-methylmorpholine-N-oxide (NMO) as co-oxidant and also found efficient catalyst in the transfer hydrogenation of ketones. The antifungal properties of the complexes have also been examined and compared with standard Bavistin.

A comparison of the fungicidal activity of amphotericin B and posaconazole against Zygomycetes in vitro

Zygomycoses is a rapidly progressive infection associated with high mortality. Although amphotericin B (AMB) has been the only treatment option for years, recent studies have demonstrated that posaconazole (PCZ) has good activity against Zygomycetes. Because rapid onset of antifungal activity is crucial in the management and never studied before, we compared the time for maximum fungicidal activity of AMB versus PCZ using time-kill curves. The MIC of AMB and PCZ against clinical isolates of Mucor spp. and Rhizopus spp. was determined by the Clinical and Laboratory Standards Institute M38-A2 method, and the fungicidal activity was examined by time-kill studies. AMB was rapidly fungicidal, with 95% killing noted as early as 6 h and 99.9% killing at 24 h; PCZ showed <70% killing at 6 h and 99.9% killing at 48 h. In vivo animal studies using AMB in the early phase, followed by a switch to high-dose PCZ later, could provide data that may have clinical implications because there are only a few drugs currently available for the management of zygomycoses.

Influence of plant growth hormones on the growth of Mucor rouxii and chitosan production

Supplementation of molasses-salt medium with plant growth hormones, viz., indoleacetic acid, indolebutyric acid, kinetin and gibberellic acid, increased chitosan production by Mucor rouxii as well as its growth at different optimum concentrations. The increase in yield of chitosan was found to range from 34% to 69% and mycelial growth from 12% to 17.4%. Gibberellic acid was the most potent in this respect. Sixty-nine percent more chitosan over the control could be obtained from 1l of the medium supplemented with 3mg gibberellic acid. Degree of acetylation of chitosan ( approximately 13%) was not changed due to addition of hormone in the medium but weight average molecular weight of chitosan increased by more than 50%. Thus, the plant growth hormones add a value to chitosan by increasing its molecular weight.

[Metabolic characteristics and lipid composition of yeastlike cells and mycelium of Mucor circinelloides var. lusitanicus INMI grown at a high glucose content in the medium]

It is shown that the fungus Mucor circinelloides var. lusitanicus INMI grown under aerobic conditions in a medium with a high glucose concentration (20%) is capable of both yeastlike and mycelial growth. In the mycelium, the activity of NAD-dependent isocitrate dehydrogenase was more than twice as high as in yeastlike cells, whereas the isocitrate lyase activity was lower. A number of significant differences were found in the lipid composition of the cells of two different morphological variants. Yeastlike cells contained more polar lipids and free fatty acids and less principal reserve lipids (triacylglycerides) than mycelial cells; the content of gamma-linolenic acid and the degree of lipid unsaturation were significantly lower in these cells than in the mycelium. In yeastlike cells, glycolipids composed the bulk of polar lipids; the proportion of phospholipids (primarily phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine, and cardiolipin) was lower. The relationship between cellular metabolism and the lipid composition of fungal cells of different morphotypes grown at high concentrations of glucose, one of the main inducers of dimorphic growth, is discussed.

Antifungal activity of essential oils against filamentous fungi determined by broth microdilution and vapour contact methods

AIMS

The in vitro activity of some essential oils (EO) (thyme red, fennel, clove, pine, sage, lemon balm and lavender) against clinical and environmental fungal strains was determined.

METHODS AND RESULTS

The minimal inhibitory concentrations were determined by a microdilution method in RPMI 1640 and by a vapour contact assay. The composition of oils was analysed by gas chromatography (GC) and GC/mass spectrometry. The results indicated that the oils antifungal activity depended on the experimental assay used. The inhibiting effects of EO in vapour phase were generally higher than those in liquid state. According to both methods thyme red and clove were found to be the oils with the widest spectrum of activity against all fungi tested.

CONCLUSIONS

Despite the differences between the two methods, our results demonstrate that some EO are very active on dermatophytes and dematiaceous fungi. However, more data will be necessary to confirm this good in vitro efficacy.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study could identify candidates of EO for developing alternative methods to control environmental and clinically undesirable filamentous fungi.

Successful treatment and limb salvage of mucor necrotizing fasciitis after kidney transplantation with posaconazole

This is a case of mucormycosis complicated by necrotizing fasciitis in a renal transplant recipient on immunosuppressive therapy treated with posaconazole. Mucormycosis occurs most commonly as an opportunistic infection in the immunocompromised host. This patient, with predisposing risk factors for infection, including diabetes mellitus status post cadaveric renal transplantation on immunosuppressive therapy, is the first reported case of successful treatment of Mucor involving an extremity which was neither fatal nor required extremity amputation.

Mucor rouxii ultrastructure: cyclic AMP and actin cytoskeleton

A comparative analysis of the effect of two compounds, dibutyryl-cyclic-AMP (dbcAMP) and latrunculin B, on the morphology and ultrastructure of the dimorphic fungus Mucor rouxii under aerobic growth conditions is presented. dbcAMP acts through the sustained activation of protein kinase A, and latrunculin B through the disruption of the actin cytoskeleton. Upon addition of these compounds to the growth medium at any stage of the germination process, cells lost polarised growth and switched to isodiametric growth. The effect was reversible. The morphologies, visualised by light microscopy or scanning electron microscopy (SEM), were alike. A switch from a rough to a smooth surface was observed by SEM when cells were repolarised by removal of the added compound. Ultrastructural changes under both conditions, as observed by transmission electron microscopy, were similar, the main feature being the enlargement of the cell wall, with irregular depositions, and detachment from the cell membrane. dbcAMP-treated cells showed a decrease in the number of glycogen granules compared with control and latrunculin B-treated cells. F-actin staining with fluorescein isothiocyanate-phalloidin showed that both dbcAMP- and latrunculin B-treated cells displayed a much lower fluorescence than control cells, with only a few pale plaques. The results suggest that the sustained activation of protein kinase A, which impairs polarised growth, might exert its effect through a modification of actin cytoskeleton organisation, very probably also involving an integrinlike pathway, as judged by the cell wall detachment and loss of cell adhesiveness of the dbcAMP-treated isodiametric cells.

Carneic acids A and B, chemotaxonomically significant antimicrobial agents from the xylariaceous ascomycete Hypoxylon carneum

Carneic acids A and B (1, 2) are polyketide antibiotics structurally related to phomopsidin. They were isolated as major constituents of the stromata of Hypoxylon carneum, a species that had shown a highly specific secondary metabolite profile in a survey of xylariaceous ascomycetes based on HPLC profiling. Their chemical structures were elucidated by a combination of spectroscopic methods and by preparation of derivatives. An X-ray crystal structure of the dinitrobenzoate of carneic acid B methyl ester (8) was obtained, even allowing for determination of its absolute structure. The carneic acids showed weak antibacterial and moderate antifungal activities in the serial dilution assay against selected microbial organisms. They appear to be species-specific marker molecules in H. carneum from different geographic regions, but do not constitute major metabolites of more than 100 species of Xylariaceae. Their biological and chemotaxonomic significance is discussed.

Transformation of Mucor circinelloides with Autoreplicative Vectors Containing Homologous and Heterologous ARS Elements and the Dominant Cbxr Carboxine-Resistance Gene

Mucor circinelloides transformants prototrophic to leucine and resistant to carboxine (Leu(+) Cbx(r)) have been obtained by treatment of protoplasts with plasmid constructs containing homologous leuA gene and adjacent autonomously replicating sequences (ARS) element combined with the Cbx(r)(carboxine-resistance) gene of Ustilago maydis and ARS sequences from this basidiomycete (plasmid pGG37) or from the 2 mu plasmid of Saccharomyces cerevisiae (plasmid pGG43). The presence in the same plasmid molecule of the M. circinelloides leuA gene and adjacent ARS element together with heterologous ARS elements produced an increase in the transformation frequency of about 65-120%. The presence of autoreplicating plasmid molecules in the transformants was demonstrated by mitotic stability experiments, by Southern analysis, and by the rescue of plasmids from transformed bacterial cells.

Fed-batch Cultivation of Mucor indicus in Dilute-acid Lignocellulosic Hydrolyzate for Ethanol Production

Mucor indicus fermented dilute-acid lignocellulosic hydrolyzates to ethanol in fed-batch cultivation with complete hexose utilization and partial uptake of xylose. The fungus was tolerant to the inhibitors present in the hydrolyzates. It grew in media containing furfural (1 g/l), hydroxymethylfurfural (1 g/l), vanillin (1 g/l), or acetic acid (7 g/l), but did not germinate directly in the hydrolyzate. However, with fed-batch methodology, after initial growth of M. indicus in 500 ml enzymatic wheat hydrolyzate, lignocellulosic hydrolyzate was fermented with feeding rates 55 and 100 ml/h. The fungus consumed more than 46% of the initial xylose, while less than half of this xylose was excreted in the form of xylitol. The ethanol yield was 0.43 g/g total consumed sugar, and reached the maximum concentration of 19.6 g ethanol/l at the end of feeding phase. Filamentous growth, which is regarded as the main obstacle to large-scale cultivation of M. indicus, was avoided in the fed-batch experiments.

Effect of media composition and in vitro activity of posaconazole, caspofungin and voriconazole against zygomycetes

OBJECTIVES

The effect of different media and composition on the in vitro activity of posaconazole, caspofungin and voriconazole against 59 zygomycetes species was determined.

METHODS

The media tested were RPMI 1640 medium with and without 2% glucose, antibiotic medium 3 (AM3) with and without 2% glucose, and high resolution (HR) medium.

RESULTS

Posaconazole was significantly more active than caspofungin and voriconazole, both in RPMI 1640 medium with 2% glucose and in HR medium. Adding glucose improved the determination of end points, but had only minor influence on the MICs. MICs evaluated in AM3 were lower than in RPMI 1640 medium or HR medium.

CONCLUSIONS

The in vivo effect of posaconazole in zygomycosis needs further evaluation.